title: Exploring the association between pain intensity and facial display in term newborns.
abstract: BACKGROUND
  Facial expression is widely used to judge pain in neonates. However, little is known about the relationship between intensity of the painful stimulus and the nature of the expression in term neonates.
  
  
  OBJECTIVE
  To describe differences in the movement of key facial areas between two groups of term neonates experiencing painful stimuli of different intensities.
  
  
  METHODS
  Video recordings from two previous studies were used to select study subjects. Four term neonates undergoing circumcision without analgesia were compared with four similar male term neonates undergoing a routine heel stick. Facial movements were measured with a computer using a previously developed 'point-pair' system that focuses on movement in areas implicated in neonatal pain expression. Measurements were expressed in pixels, standardized to percentage of individual infant face width.
  
  
  RESULTS
  Point pairs measuring eyebrow and eye movement were similar, as was the sum of change across the face (41.15 in the circumcision group versus 40.33 in the heel stick group). Point pair 4 (horizontal change of the mouth) was higher for the heel stick group at 9.09 versus 3.93 for the circumcision group, while point pair 5 (vertical change of the mouth) was higher for the circumcision group (23.32) than for the heel stick group (15.53).
  
  
  CONCLUSIONS
  Little difference was noted in eye and eyebrow movement between pain intensities. The mouth opened wider (vertically) in neonates experiencing the higher pain stimulus. Qualitative differences in neonatal facial expression to pain intensity may exist, and the mouth may be an area in which to detect them. Further study of the generalizability of these findings is needed.
authors.affiliation: University of Rochester School of Nursing, Rochester, NY, USA. martin_schiavenato@urmc.rochester.edu
authors.forename: Martin
authors.initials: M
authors.lastname: Schiavenato
authors.forename: Meggan
authors.initials: M
authors.lastname: Butler-O'Hara
authors.forename: Paul
authors.initials: P
authors.lastname: Scovanner
mesh_terms: D005149:Facial Expression; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009068:Movement / Q000502:physiology; D010146:Pain / Q000175:diagnosis* / Q000209:etiology* / Q000523:psychology*; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D010812:Physical Stimulation / Q000009:adverse effects; D011930:Reaction Time; D014741:Video Recording